1. Field of the Invention
The present invention relates to titanium dioxide aggregates and titanium dioxide aggregates treated with a mineral acid which can be applied to electrophotographic photoconductors, substrates for an electroconductivity-imparting agent, substrates for an antistatic agent, catalysts and catalyst carriers and fillers and are especially suitable for electrophotographic photoconductors.
2. Description of the Art
Titanium dioxide has high hiding power and coloring power and besides gives excellent gloss to a coating film and is used mostly as a pigment. Most of the commercially available ones are of an anatase or rutile type of 0.15-0.35.mu. in avarage particle size and are subjected to surface treatment, for example, with hydroxides of aluminum and silicon in order to improve dispersibility, gloss, weathering resistance, and the like depending on purposes.
On the other hand, zinc oxide is used in a large amount as electrophotographic photoconductors and, on the other hand, applying to electrophotography titanium dioxide in place of zinc oxide have been studied and developed.
Titanium dioxide as photoconductor is reported, for example, in Japanese Patent Kokoku (Post-Exam. Publn.) No. 47-29117. This titanium dioxide has an anatase type crystal structure and comprises particles having an average particle size of 0.05-0.15.mu., at least 70% by weight of which are within the range of 0.08-0.18.mu..
Recently, with the progress of electrophotographic technique, images of higher quality are demanded and the development of photoconductor titanium dioxide further excellent in electrophotographic characteristics has been desired.